1. The Field of the Invention
The invention relates to devices, methods, and systems for printing with thermal paper. Specifically, the invention relates to devices, methods, and systems for printing by frictionally reacting thermal paper.
2. The Relevant Art
A number of technologies have been employed for printing applications. For instance, impact printers have been used to provide high-speed, cost-effective printing. In an impact printer, a printing pin strikes a printer ribbon, transferring ink from the printer ribbon to a paper. A limiting characteristic of impact printers is that the printer ribbon requires transport and storage mechanisms within the printer. Also, printer ribbons must also be periodically changed, increasing maintenance costs. As a result, impact printers are often unsuitable for applications requiring small printer size and low maintenance, such as point-of-sale applications.
Laser printers have also been used extensively to provide high-speed printing. A laser printer deposits a charge on drum that attracts toner. The drum then transfers the toner to a paper. However, the laser printer drum requires significant space, and toner must also be periodically added. Consequently, laser printers also have typically not been used for applications requiring printers of small size and low maintenance.
Ink jet printers are also frequently used due to their low initial cost. Ink jet printers apply small jets of ink to paper. However, ink jet printers require the ink reservoir to be located close to the print mechanism, increasing the size of the printer mechanism. The print mechanism/reservoirs of an ink jet printer must also be replaced frequently, increasing the cost and maintenance of the printer. As a result, ink jet printers also have typically not been used for applications requiring small printer size, low maintenance, and low per page cost.
Thermal paper printers are used extensively in printing applications to overcome many of the limitations of impact, laser and ink jet printers, particularly in point of sale applications. Thermal paper is treated chemically to react when heated, forming a mark on the heated portion of the paper. In operation of a thermal paper printer, heating elements are used to react the thermal paper. Thermal paper printers are widely used for printing applications that demand small printer size and low maintenance, because the heating elements of the thermal paper printer require little space, and toner, ribbons, and ink reservoirs are not needed. Thermal paper printers are also attractive because little maintenance is required aside from adding paper.
In a thermal paper printer, the heat applied to each area of the thermal paper must be carefully controlled to produce a clean, legible printed copy. Some thermal papers react to specific temperature ranges by forming unique colors, making temperature control even more critical. A disadvantage of thermal paper printers is that thermal paper printer heating elements do not heat and cool immediately. Thermal printing elements often must move at slower speeds to maintain the appropriate temperatures over each portion of the thermal paper. Because printing speeds are limited by the thermal characteristics of the heating elements, typical thermal paper printers do not print as quickly as desired for many applications.
Slow printing speeds are particularly an issue in point of sale applications, where slower printing reduces a cashier's throughput. Faster thermal paper printers are desirable, because they could be used to print more detailed, informative, and useful receipts, contracts, warranties, and other customized documents. Faster thermal paper printers could also find application in other printing segments that have been impractical because of slow printing speeds.
Accordingly, what is needed is a device, method, and system for rapidly and selectively heating thermal paper. In particular, the device, method, and system should react thermal paper using frictionally generated heat. The frictional heat would optimally be generated and applied selectively at high speeds. Such a printer using frictionally generated heat to react thermal paper would print rapidly, while maintaining a thermal paper's principle advantages of small size and low maintenance. Such an improved device, method, and system would allow the rapid printing of large documents with small printers, improving the efficiency of many tasks including point-of-sale printing.